The compound 2,3-difluoroaniline is the starting raw material for producing 2-[2-fluoro-6-(7,8-difluoro-2-methylquinolin-3-yloxy)phenyl]propan-2-ol and 2-[2-fluoro-6-(7,8-difluoroquinolin-3-yloxy)phenyl]propan-2-ol, which are known as active ingredients for agricultural and horticultural germicides (Patent Document 1).
Further, 2,3-difluoroaniline is also used in the production of medicines such as antibiotics (Patent Document 2), c-Met protein kinase inhibitors (Patent Document 3), drugs for Alzheimer's disease (Patent Document 4), Aurora 13 kinase inhibitors (Patent Document 5), and drugs for neuropathic pain (Patent Document 6).
Moreover, 2,3-difluoroaniline is also used in the production of electronic materials such as the azo compounds contained in compositions for anisotropic films that exhibit high dichroism, which are useful in the polarizing plates and the like fitted to display elements such as liquid crystal display elements (LCD) and organic electroluminescent display elements (OLED) (Patent Document 7).
In this manner, 2,3-difluoroaniline is useful as a production raw material for electronic materials, medicines and agricultural chemicals, and a simple method for producing 2,3-difluoroaniline cheaply and in large quantities has been keenly sought.
One example of a known method for producing 2,3-difluoroaniline involves fluorinating 2,3-dichloronitrobenzene to obtain 3-chloro-2-fluoronitrobenzene, hydrogenating the 3-chloro-2-fluoronitrobenzene to obtain 3-chloro-2-fluoroaniline, using the Schiemann reaction to convert the 3-chloro-2-fluoroaniline to 2,3-difluorochlorobenzene, and then performing an amination reaction with a copper catalyst to produce 2,3-difluoroaniline (Patent Document 8).

This method requires high temperature and high pressure in the fluorination reaction and the amination reaction, and uses chemical reagents that are difficult to handle such as Raney nickel, and can therefore not really be claimed to be an industrially useful method.
Patent Document 9 discloses that 2,3-difluoroaniline can be obtained by fluorinating 1,2,3-trichlorobenzene to obtain 2,3-difluorochlorobenzene, and then aminating the 2,3-difluorochlorobenzene using a copper catalyst.

However, in this method, a regioisomer (2,6-difluorochlorobenzene) is produced as a by-product during the fluorination, and therefore the yield of 2,3-difluorochlorobenzene is low. Further, the separation of the 2,3-difluorochlorobenzene from the by-product regioisomer is extremely difficult. Moreover, high temperature and high pressure conditions are required in the fluorination and amination reactions, meaning this method can also not be claimed to be industrially useful.
Patent Document 10 discloses a method for producing 2,3-difluoroaniline by hydrogenating 2,3-difluoronitrobenzene at high pressure.

This method is simple, having only one step, and is industrially feasible, but the raw material 2,3-difluoronitrobenzene is extremely difficult to obtain, and the only known method in the literature involves oxidation of the target material 2,3-difluoroaniline.
Patent Document 11 discloses a method for producing 2,3-difluoroaniline by hydrogenating 2,3-difluoro-4-chloro-nitrobenzene. However, in this method also, the raw material 2,3-difluoro-4-chloro-nitrobenzene is extremely difficult to obtain.
As described above, currently known methods for producing 2,3-difluoroaniline require high temperature and high pressure reactions, and not only are the equipment costs high due to the requirement for special production equipment, but safety and stability operations are also a significant burden.